Wireless power transfer systems have been developed for a variety of different applications, including battery charging applications for vehicles, mobile electronic devices, tools, and the like. Such systems can use magnetically coupled resonant circuits to transfer energy. Examples of such wireless power transfer systems are described in U.S. Pat. No. 8,531,059 and U.S. Patent Application Publication No. 2013/0249479.
An example of control of a wireless power transfer system is described in U.S. patent application Ser. No. 14/323,436, entitled WIRELESS POWER TRANSFER SYSTEMS USING LOAD FEEDBACK, filed Jul. 3, 2014.
U.S. patent application Ser. No. 14/143,505 entitled METHODS, CIRCUITS AND ARTICLES OF MANUFACTURE FOR CONFIGURING DC OUTPUT FILTER CIRCUITS, filed Dec. 30, 2013, describes wireless power transfer systems having a transmitter including a rectifier that receives power from an AC power source, an inverter circuit that generates a higher frequency AC output voltage from a DC output produced by the rectifier, and a first resonant circuit coupled to an output of the inverter circuit. A receiver includes a second resonant circuit including a coil that is configured to be placed in close proximity to a coil of the first resonant circuit and a rectifier circuit that produces a DC output from an AC output produced by the second resonant circuit.
FIG. 1A is a block diagram illustrating a power distribution system that may be used in a data center that includes a plurality of racks 100 that are configured to house servers provided with 3-phase power. According to FIG. 1A, 3-phase power is provided to a 3-phase power transformer 120 that provides power, such as 480 VAC 3-phase power, to a UPS system 115. The UPS system 115 is configured to provide power to the servers even if the 480 VAC 3-phase power to the UPS system 115 fails.
The UPS system 115 provides 480 VAC 3-phase power to a power distribution unit (PDU) 105 which is configured to step-down the 3-phase power to a lower power level, such as 208 VAC 3-phase power. It will be understood that the 3-phase power can be provided at a low frequency, such as 50 or 60 Hz. The 208 VAC 3-phase power is provided to the plurality of racks 100 via a branch circuit 110. The branch circuit 110 can be a network of electrical conductors that couple the output of the PDU 105 to all of the racks 100, for example, in parallel.
FIG. 1B is a block diagram that illustrates a server power supply 150 that receives the 208 VAC 3-phase power shown in FIG. 1A over the branch circuit 110. In particular, the 208 VAC 3-phase power can be provided to a 3-phase power factor control circuit 160 in the power supply 150 to generate a DC voltage (such as 380 VDC). The DC voltage can be provided to a DC-DC converter 155 to step-down the DC voltage to a level that may be utilized by the servers housed in the racks 100. It will be understood that each of the servers included in each of the racks 100 can include a version of the server power supply 150, and therefore may be provided with the 208 VAC 3-phase power.